
table {
    width: 90%;
    margin: 30px auto;
    border-collapse: collapse;
}
th,td {
    height: 25px;
    line-height: 25px;
    text-align: center;
    border: 1px solid #ccc;
}
th {
    background: #eee;
    font-weight: normal;
}

tr:hover {
    background: #f3e0a3;
    /*设置被鼠标悬浮时的颜色*/
}

td a {
    color: #2e6ed0;
    text-decoration: none;
}

td a:hover {
    color: #2e6ed0;
    text-decoration: underline;
}
.button{
    background-color: #333;
    border: none;
    cursor: pointer;
    text-align: center;
    color: white;
    box-shadow: 0 2px 4px 0 rgb(0 0 0.2), 0 2px 4px 0 rgb(0 0 0.2);
    margin-top: 10px;
    width: 180px;
    height: 30px;
    margin-left: 650px;
}
a{
    color: white;
}
#tip{
    margin-top: 20px;
    margin-left: 570px;
}